D. Chan and P. Trinder, Object-Comprehension: A Query Notation for Object-Oriented Databases, Proc. 12-th British Conference on Databases, pp. 55-72, 1994, LNCS 826.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... a variety of query transformation and optimization algorithms, and in particular those designed for expensive predicates [CS93, HS93, H94, KMPS94] We adopt a variant of monoid comprehension calculus [FM95] which is based on monoid homomorphisms [BTBN91, BTS91, BTBW92] and monad comprehensions [TW89, W90, CT94], as a query evaluation platform. This decision is motivated by the fact that the monoid calculus is formally, and accurately defined, and readily captures such features as extensible multiple collection types, aggregations, arbitrary compositions of type constructors and nested query expression, ....

D. Chan and P. Trinder, Object-Comprehension: A Query Notation for Object-Oriented Databases, Proc. 12-th British Conference on Databases, pp. 55-72, 1994, LNCS 826.

....type. This mixing is not possible for monad comprehensions, since they restrict the inputs and the output of a comprehension to be of the same type. Monad comprehensions were rst proposed as a convenient database language by Trinder, Chan, and Wadler [Trinder and Wadler 1989; Trinder 1991; Chan and Trinder 1994], who also presented many algebraic transformations over these forms as well as methods for converting comprehensions into joins. The monad comprehension syntax was also adopted by Buneman et al. 1994] as an alternative syntax to monoid homomorphisms. The comprehension syntax was used for ....

Chan, D. and Trinder, P. 1994. Object Comprehensions: A Query Notation for ObjectOriented Databases. In Twelfth British Conference on Databases, Guildford, United Kingdom (July 1994), pp. 55-72. Morgan Kaufmann Publishers, Inc. LNCS 826.

....may return output of a di erent type. This mixing is not possible for monad comprehensions, since they restrict the inputs and the output of a comprehension to be of the same type. Monad comprehensions were rst proposed as a convenient database language by Trinder, Chan, and Wadler [TW89, Tri91, CT94] who also presented many algebraic transformations over these forms as well as methods for converting comprehensions into joins. The monad comprehension syntax was also adopted by Buneman, et al. BLS 94] as an alternative syntax to monoid homomorphisms. The comprehension syntax was used for ....

D. Chan and P. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In Twelfth British Conference on Databases, Guildford, United Kingdom, pages 55-72. Morgan Kaufmann Publishers, Inc., July 1994. LNCS 826.

.... variety of query transformation and optimization algorithms, and in particular those designed for expensive predicates [CS93, HS93, H94, KMPS94] 4 We adopt a variant of monoid comprehension calculus [FM95] which is based on monoid homomorphisms [BTBN91, BTS91, BTBW92] and monad comprehensions [TW89, W90, CT94], as a query evaluation platform. This decision is motivated by the fact that the monoid calculus is formally, and accurately defined, and readily captures such features as extensible multiple collection types, aggregations, arbitrary compositions of type constructors and nested query expression, ....

D. Chan and P. Trinder, Object-Comprehension: A Query Notation for Object-Oriented Databases, Proc. 12-th British Conference on Databases, pp. 55-72, 1994, LNCS 826.

....written in Prolog, and a partial match retrieval scheme, called SIMC, for external databases. SIMC is based on superimposed codewords and provides multikey access at both the segment and record levels. The contents of the database are summarised in Figure 2 using an object data model notation [9]. Rectangles represent classes; dashed arrows represent the is a relationship; arrows represent single valued methods (attributes) while arrows with ellipses represent multi valued methods, with the name in the ellipse indicating the type of collection, List, Set, or Bag, returned. This is a ....

....and the variety of retrieval mechanisms needed to support mathematical databases. To this end, we are constructing a C framework [3] which initially includes a Datalog interpreter, multi attribute retrieval mechanisms, and an interpreter for TwoGroups. The idea of object comprehension [9], which provides declarative querying of object oriented databases, is a natural development from the set comprehension query language of TwoGroups and addresses several extensions that are of interest to us. These include complex objects, user defined functions, and query optimisation. We are ....

Chan, D.K.C., and Trinder, P.W., "Object comprehension: A query notation for object-oriented databases", to appear in Proceedings of 12th British National Conference on Databases, Guildford, July 1994, Springer-Verlag.

....return output of a different type. This mixing is not possible for monad comprehensions, since they restrict the inputs and the output of a comprehension to be of the same type. Monad comprehensions were first proposed as a convenient database language by Trinder, Chan, and Wadler [TW89, Tri91, CT94] who also presented many algebraic transformations over these forms as well as methods for converting comprehensions into joins. The monad comprehension syntax was also adopted by Buneman, et al. BLS 94] as an alternative syntax to monoid homomorphisms. The comprehension syntax was used for ....

D. Chan and P. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In Twelfth British Conference on Databases, Guildford, United Kingdom, pages 55--72. Morgan Kaufmann Publishers, Inc., July 1994. LNCS 826.

....objects. 4. Work by people such as Ehrich, Sernadas and Sernadas [26] 27] 50] Kim [39] Lu and Dillon [44] and books such as [29] 35] describe or specify a flavour of the OO data model. Alashque, Su and Lam [3] Bancilhon, Briggs et al. 6] Negri, Pelagatti et al. 10] Chan and Trinder [19]; Ishikawa, Suzuki and Kozakura et al. 36] Kim [38] and L ecluse and Richard [43] also present query languages on the data model. These papers define different varieties of the OO data model and OO databases, which we will review in section 5. The rest of this article is divided into the ....

....syntax. The syntax is defined fairly formally and many examples are given, but there is no model of the semantics. Two types of object equality (identity and value) are discussed. The use of methods in path expressions is permitted and the notion of a quantified path expression is explored. 3. In [19] Chan and Trinder specify a query language using a notation called object comprehensions based on the well understood concept of set comprehensions. A good overview and explanation of the query language is given which allows an interesting family of expressions. The paper also claims that their ....

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D.K.C. Chan and P.W. Trinder. Object comprehensions: a query notation for object-oriented databases. In Lecture Notes in Computer Science, volume 826. Springer-Verlag, 1994.

....collection types and may return output of a different type. This is not possible for monad comprehensions, since they restrict the inputs and the output of a comprehension to be of the same type. Monad comprehensions were first proposed as a convenient and practical database language by P. Trinder [27, 26, 10], who also presented many algebraic transformations over these forms as well as methods for converting comprehensions into joins. The monad comprehension syntax was also adopted by P. Buneman, et al. 8] as an alternative syntax to monoid homomorphisms. The comprehension syntax was used for ....

D. Chan and P. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In Twelfth British Conference on Databases, pp 55--72, July 1994. LNCS 826.

....and load balancing, and accurate cost prediction within the BSP model. Our main technical contributions, so far, are the identification of an adequate set of basic collection types and operations, a mathematical framework for the uniform treatment of such collections based on the works of [34, 53, 130], and some encouraging results from a preliminary BSP implementation of an object database query evaluator. In the rest of this chapter, we briefly introduce the architectural advancements beginning to enable general purpose parallel computing, review the work done on models of parallel ....

D. Chan and P. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In 12th British Conference on Databases. LNCS 826, Springer-Verlag, July 1994.

....To manipulate the rich structures found in these data models a query language will require more constructs. Often this is resolved by extending a relational query language with ad hoc features. Object comprehensions were specifically designed as a query language for object oriented databases [14] and shown to be at least as powerful as several other prominent query languages [10] It is essential that a query can be converted into an efficient execution plan, and this typically entails translating it into a small set of primitive operations. The operations form an algebra because there ....

.... theoretical studies of query languages [7,17] Its role as an internal representation language for the ODMG 93 OQL [9] is investigated in [19] Object comprehensions differ from other dialects of comprehensions in that they are designed to be a user query language for object oriented databases [14] as opposed to just a vehicle for optimisation as in [30,19] or a notation for studying the theoretical foundation of query languages as in [7,17] The design criteria adopted are thoroughly discussed in [15] A comparison of object comprehensions with ONTOS SQL [29] OSQL [24] O 2 SQL [3] ORION ....

D.K.C. Chan and P.W. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In Proceedings of the British National Conference on Databases, volume 826 of Lecture Notes in Computer Science, pages 55--72. Springer-Verlag, 1994.

....Harper, and Ray Welland. A fair amount of the materials presented in Chapter 2, 3, 4, and 8 of this thesis has been published before in various technical reports, workshop proceedings, conference proceedings, and the Computer Journal [TCH90, CHT92a, CHT92b, CT93, CHT93a, CHT93b, CK94, CT94a, CT94b, CTW95] All the papers involve more than one author and the co authors include Phil Trinder, David Harper, Ray Welland, and David Kerr. However the author is responsible for the majority of the technical substance of these papers and of this thesis. iv Acknowledgements It is a great pleasure ....

D.K.C. Chan and P.W. Trinder. Object Comprehensions: A Query Notation for Object-Oriented Databases. In Proceedings of the British National Conference on Databases, volume 826 of Lecture Notes in Computer Science, pages 55--72. Springer-Verlag, 1994. Bibliography 157

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